On the Failure Initiation in the Proximal Human Femur Under Simulated Sideways Fall

Area of Science:

• Biomechanics
• Orthopedic research
• Medical imaging analysis

Background:

• Areal bone mineral density (aBMD) has limitations in predicting hip fracture risk.
• Quantitative CT (qCT) enables geometrical and finite element analysis (FEA) for improved risk assessment.
• Current FEA methods require further development for clinical application.

Purpose of the Study:

• Correlate proximal femur geometry with impact-induced peak force.
• Determine fracture initiation sites in the proximal femur.
• Investigate the role of cortical perforations in fracture initiation.

Main Methods:

• Subject-specific FEA using qCT data.
• Simulated sideways fall impact testing.
• Macro and micro level FE simulations.

Main Results:

• Cortical thickness in the trochanteric-fossa strongly correlated with peak force (R²=0.69).
• Femoral neck cortical thickness showed a weaker correlation (R²=0.15).
• FE simulations indicated fracture initiation in cancellous bone, with potential involvement of surface holes.

Conclusions:

• Proximal femur geometry, particularly trochanteric-fossa cortical thickness, is a significant predictor of femoral strength.
• FEA can predict fracture initiation sites, highlighting the role of cancellous bone and surface defects.
• These findings advance the development of advanced hip fracture screening tools.